Understanding the enhanced electrorheological effect of reduced graphene oxide‐supported polyaniline dielectric nanoplates by a comparative study with graphene oxide as the support core

Abstract

Graphene has attracted scientific interest as a substrate or additive for developing highperformance stimuli-responsive materials. Research on graphene-based polymer dielectric composites has shown an enhanced electroresponsive electrorheological (ER) effect. However, the mechanism behind the enhanced electroresponse is still incompletely understood. Here, an investigation was performed into dielectric polarization and the ER effect of reduced graphene oxide-supported polyaniline nanoplates by comparing them with pure granular polyaniline and graphene oxide-supported polyaniline nanoplates based on dielectric spectroscopy and rheologic analysis. We discovered that both anisotropic morphology and electrical properties have dominant roles in the enhanced ER effect of reduced graphene oxide-supported polyaniline nanoplates, whereas only anisotropic morphology has a dominant role in the enhanced ER effect of graphene oxide-supported polyaniline nanoplates. The analysis also showed that reduced graphene oxide-supported polyaniline nanoplates have a good ER response to both DC and AC electric field actions in the wide shear rate region. This is highly desirable for practical engineering applications. Therefore, the analysis reveals the reason for the enhanced ER effect of reduced graphene oxide-supported polyaniline nanoplates and also may provide a guide for designing high-performance ER materials for practical engineering applications by combining the advantages of conducting a reduced graphene oxide core and ER active shell.This is an open access article under the terms of the Creative Commons Attribution-NonCommercial-NoDerivs License, which permits use and distribution in any medium, provided the original work is properly cited, the use is non-commercial and no modifications or adaptations are made.

Electrorheological Fluids of GO/Graphene-Based Nanoplates

“…Yin et al [ 83 , 84 ] developed graphene-based composite nanoplate ER fluids by combining rGO with a semi-conducting polymer such as polyaniline and polypyrrole. As shown in Figure 6 a, they first prepared PANI-coated GO composite nanoplates by the in situ polymerization method and then skillfully reduced PANI from a conductive state to an insulating state and reduced GO from an insulating state to a conductive rGO state by hydrazine treatment, thus forming composite nanoplates with a conductive rGO core and insulating PANI shell [ 85 ]. Figure 6 b shows the SEM and TEM images of rGO/PANI composite.…”

“… ( a ) Schematic preparation of GO/PANI by in situ polymerization of aniline on the surface of GO and the resulting rGO/PANI by hydrazine treatment of GO/PANI [ 85 ]; ( b – e ) SEM and TEM images of GO/PANI and rGO/PANI [ 83 ], both are ~150 nm thick. …”

Nano‐materials for engineering application

“…Reference [6], 'Understanding the enhanced electrorheological effect of reduced graphene oxide-supported polyaniline dielectric nanoplates by a comparative study with graphene oxide as the support core' (by Yuan, J. et al), presents a comparative study with graphene oxide as the support core. The authors have given guidelines for designing highperformance electrorheological materials useful for practical engineering applications.…”

“…Reference [6], ‘Understanding the enhanced electrorheological effect of reduced graphene oxide‐supported polyaniline dielectric nanoplates by a comparative study with graphene oxide as the support core’ (by Yuan, J. et al. ), presents a comparative study with graphene oxide as the support core.…”

Engineering Conductivity and Performance in Electrorheological Fluids Using a Nanosilica Grafting Approach

“…The ER fluid based on GO/PANI exhibited only a slow relaxation process with a relaxation time, t rel , t rel,1 = 1.4 × 10 −3 s, whereas the one based on the particles with a conducting core from rGO showed a similar relaxation process t rel,1 = 1.3 × 10 −3 s, arising from the semiconducting PANI shell, as well as fast interfacial polarization with a relaxation of t rel,2 = 1.4 × 10 −8 s. Therefore, despite similar particle size, morphology, and conductivity, the ER fluid based on rGO/ PANI exhibited significantly enhanced ER behavior due to the high conductivity of the core rGO and its enhanced intensity and rate of interfacial polarization. 20 Unlike GO/PANI composites exhibiting a single relaxation process, a system based on poly(ethylaniline)-coated GO exhibited two clear relaxation processes observed at impedance spectroscopy affecting the flow properties of ER fluids. 21 Graphene is another interesting material; however, it is too conducting for its use in electrorheology and is therefore typically modified.…”